The presentation describes how to asses aortic valve during Transesophageal Echocardiography

1. TEE Quantification of Aortic Stenosis and Aortic Regurgitation Dr PK Neema

2. Normal Aortic valve ME Sax view transducer at 40o

3. Normal flow-dynamics Aortic velocity Vmax 1-1.2m/sec LVOT max velocity 0.9-1.1 m/sec P2 V1 = V2 P1 = P2 V2 V1 P1

4. AS and its effect on Flow-dynamic P1 > P2 V2 > V1

5. Doppler principle

6. Effect of interrogation angle on frequency shift

7. Ultrasound beam should be parallel to the flow under study The ultrasound should intercept the center of the flow not the periphery The interrogation angle should be < 15o The view optimal for the imaging may not be the optimal view for the Doppler study Essentials during Doppler study

8. Transgastric Lax view (Transducer at 130o) TEE Views for Doppler study

9. Deep Transgastric Lax view TEE Views for Doppler study

10. Simplified Bernoulli equation Continuity equation Methods to quantify AS

11. Simplified Bernoulli equation P = 4V2 2 P – Pressure gradient Severe AS = P > 75 mmHg

12. Deep Transgastric Lx View

13. Peak velocity Mean velocity Peak gradient 4V2 Mean gradient Velocity time integral (VTI) or TVI Measurements

14. Continuity equation

15. Continuity equation Blood flow through LVOT = Blood flow through AoV Blood flow through LVOT = CSA LVOT X TVI LVOT Blood flow through AoV = CSA AoV X TVI AoV CSA LVOT X TVI LVOT = CSA AoV X TVI AoV CSA AoV = LVOT flow/TVI AoV

16. The LVOT diameter is measured in ME Lax view at 130o and measured from endocardium to endocardium at the level of insertion of AV leaflets in midsystole Inaccuracy in the measurement of diameter can result in gross error since the radius of the LVOT is squared for calculating area (CSA = πr2) Assessment of LVOT area ME Lax View Xducer at 130o

17. The TVI is measured by Doppler interrogation through LVOT using pulse wave Doppler (PWD) The sample volume is assessed just proximal to the aortic valve within the LVOT where the annular dimension is measured TVI Measurement in LVOT Transgastric Lax view

18. Severity of AS

19. AS and Mitral regurgitation Low cardiac output Aortic regurgitation Fallacies

20. The MR jet can be mistaken for that of AS. How to avoid the MR jet? The MR jet should be visualized during colour Doppler imaging and the MR jet path should be consciously avoided. How to confirm? The MR jet starts early with LV contraction, the AS jet starts later in systole. The MR jet starts in the early portion of QRS complex while AS jet starts in the mid or late portion of QRS complex. Determination is facilitated by recording the jets at a faster sweep speed (100 mm/s) AS and Mitral regurgitation (MR)

21. Gorlin formula (AVA = Cardiac output/ 44.3 (SEP) (HR) √mean gradient The CO is an important determinant of valve area and a decrease in CO result in a decrease in the peak aortic gradient and the severity of AS Accordingly, one should assess LV function before ‘small gradients’ are reported as insignificant. Dobutamine stress test and dimensionless index are evaluated to assess AS severity in presence of low CO. AS and Low cardiac output

22. High CO, similar to low CO, result in over estimation of peak gradient and AS severity. The discrepancy is corrected by measuring the blood flow velocity in the LVOT and applying a correction if the measured LVOT peak velocity exceeds 1.5 m/s. Peak gradient in presence of significant aortic regurgitation = 4 [(peak velocity)2 – (LVOT velocity)2] AS and Aortic regurgitation

23. Dobutamine (5-10 μg/kg/min) is infused to increase CO An increase in pressure gradient suggests severe valvular disease. No or borderline increase in pressure gradient suggest primary myocardial disease as the cause of low gradient and contraindicate valve replacement as the primary therapy; However, AS is a unique cardiovascular disease where patients with a low EF may normalize after valve replacement. Dobutamine stress test

24. LVOT and aortic TVI ratio or peak LVOT and aortic velocity ratio of 0.25 or less indicates critical AS. Useful in evaluation of patients with prosthetic aortic valves where measurement of aortic annular dimensions is not clear. Dimensionless index

25. Aortic Regurgitation ME Lax view Transducer at 130o

26. Based on Color flow Doppler (Jet width and jet area measurement) Continuity equation Regurgitant jet velocity assessment AR quantification

27. TEE view for jet width measurement ME Lax view Transducer at 130o

28. Jet width to LVOT diameter ratio Jet width-LVOT diameter ratio > 65% indicate severe AR

29. Color M mode 75/ 214 =0.35

30. LVOT Shadowing Aortic prosthesis Mitral prosthesis Site and shape of the orifice (Eccentric jet, multiple jet) Jet width limitations

31. TEE views for jet area measurement ME Sax view Transducer at 40o

32. 1+ < 4% (trivial) 2+ 4-24 (mild) 3+ 25-59 (moderate) 4+ >60 (severe) Jet area/LVOT area

33. Vena Contracta Vena Contracta width of > 6 mm indicate Severe AR

34. Blood flow through LVOT = CSA LVOT X TVI LVOT Blood flow through RVOT = CSA RVOT X TVI RVOT Regurgitant volume = CSA LVOT X TVI LVOT – CSA RVOT X TVI RVOT EROA = Regurgitant volume/VTI (VTI measured by PWD) Continuity equation

35. Deceleration Slope and Pressure-half time The velocity of regurgitant jet during diastole is directly related to pressure gradient between aortic root and LV. A large regurgitant defect will rapidly decrease pressures gradient and the velocity of regurgitant jet, hence slope of AR jet indicate severity of AR CWD analysis of AR jet transgastric or deep transgastric view

36. Regurgitant jet Slope Decay Mild AR Severe AR (>3m/sec2) CWD LVOT Ao Ao LV pressure LV

37. LVEDP – Ischemia, LV dysfunction Low Aortic diastolic pressure Eccentric jets Acute AR vs. C/c AR CWD-Deceleration slope limitations

38. Holo-diastolic flow reversal Severe AR

39. Severity of Regurgitation 3-6 mm <3 mm